Nanzhe Jiang

High surface area TiO2–ZrO2 prepared by caustic solution treatment, and its catalytic efficiency in the oxidehydrogenation of para-ethyltoluene by CO2

High surface area TiO2–ZrO2 (1 : 1) has been synthesized by co-precipitation—digestion method using KOH solution as a hydrolyzing agent as well as a digestion medium. The quenching of the mother liquor solution at elevated temperatures resulted in the amorphization of the TiO2–ZrO2 mixed oxide. The highest surface area obtained for TiO2–ZrO2 by the co-precipitation–digestion method is 256 m2 g−1 calcined at 600 °C with complete amorphous nature and having a particle size of less than 5 nm. Herein, we discuss the concept of amorphization of metal oxides based on the digestion times, supported by the characterization of the catalysts and its application in dehydrogenation of substituted benzene, mainly para-ethyltoluene to para-methylstyrene by CO2 as soft oxidant which showed high conversion and selectivities of 69% and 96%, respectively.

Lewis-type catalytic activity of direct incorporated Zr- and Sn-SBA-16 catalysts

Metal incorporation into nanoporous materials could give Lewis acid sites through the framework substitution of silica matrix, which are supposed to be in tetrahedral substitution of silica. In this work, Zr- and Sn-incorporated SBA-16 were directly synthesized by the microwave synthesis method. These microwave synthesized Zr- and Sn-incorporated mesoporous silica materials were applied in activation of ketones by Lewis acid sites to catalyze Meerwein-Ponndorf-Verly reduction of cyclohexanone and Baeyer-Villiger oxidation of adamantanone, respectively. Optimum incorporated Zr- and Sn-species gave almost 100% selectivity with high activity onto corresponding alcohol and lactone, respectively.

Oxidative Dehydrogenation of Ethylbenzene to Styrene with CO 2 Over V 2 O 5 –Sb 2 O 5 –CeO 2 /TiO 2 –ZrO 2 Catalysts

Utilization of CO2 as a soft oxidant in the oxidative dehydrogenation of ethylbenzene to styrene, a remarkable V2O5–Sb2O5–CeO2/TiO2–ZrO2 catalyst has been accomplished. Preparation of TiO2–ZrO2 support by co-precipitation followed by a single step deposition of V and Ce and Sb as stabilizers yielded a highly active and selective catalyst. Acid–base and redox properties including sustained stability of active species (V5+) are responsible for high activity of V2O5–Sb2O5–CeO2/TiO2–ZrO2 catalyst. The redox cycle is related to the dispersed V5+ and lattice reduced vanadium site in the VSbO4 phase. The antimony oxide inhibits the easy redox cycle between different vanadia species.

Ethylbenzene to styrene over ZrO2-based mixed metal oxide catalysts with CO2 as soft oxidant

Abstract ZrO2-based mixed metal oxide catalysts for the industrially important dehydrogenation process of ethylbenzene to styrene monomer have been explored by our group for the past 20 years. These efforts were subjected to the activation of CO2 over mixed metal oxide catalysts and resulted in several promising benefits to the dehydrogenation processes, such as stabilized conversion and selectivity, suppressed coke formation and commercially-acceptable longevity. In this review, we summarize the most recent developments on ZrO2-based mixed metal oxide catalysts, including the further optimization of sol-gel process in the synthesis of catalysts, rationalizing acid-base properties by doping, co-operative properties between redox and acid-base active sites and additional promoters towards the effective improvement of the longevity of catalysts.

Microwave synthesis of Zr incorporated SBA-16 mesoporous silica as a catalyst for Meerwein-Ponndorf-Verley (MPV) reduction

Zr incorporated and pure SBA-16 were prepared by microwave synthesis method. These microwave synthesized Zr-SBA-16 played a role as Lewis acid sites for the Meerwein-Ponndorf-Verly reduction of ketones giving almost 100 % selectivities with high activities.

Microwave synthesis of SBA-15 mesoporous silica material for beneficial effect on the hydrothermal stability

Hydrothermally robust mesoporous SBA-15 silica material was synthesized for the first time using microwave with out adding any other chemical ingredients. For the sake of stability comparison, mesoporous SBA-15 material was also prepared by conventional hydrothermal technique. The stability of the material was tested by boiling water method and 29 Si-NMR Q 4 /Q 3 ratios. It was observed that SBA-15 synthesized under microwave conditions exhibited higher stability than that of hydrothermally synthesized SBA-15.